Chemically-amplified positive resist composition and patterning process thereof

Abstract

There is disclosed a chemically-amplified positive resist composition comprising, as main components, (A) a base polymer, which contains one or more kinds of a monomer unit represented by the following general formula (1) and the like, and is an alkali-insoluble polymer whose hydroxyl group is partly protected by an acetal group while alkali-soluble when deprotected by an acid catalyst, (B) a sulfonium salt containing a sulfonate anion, (C) a basic component, and (D) an organic solvent. In a lithography technology by a photo resist, an extremely high temporal stability is necessary. In addition, it must give a good pattern profile not dependent on a substrate and have a high resolution power. There can be provided a chemically-amplified positive resist composition which can solve these problems simultaneously, a resist patterning process using the same, and a method for producing a photo mask blank.

1. A chemically-amplified positive resist composition comprising, as its main components, at least (A) a base polymer consisting of one or more monomer unit represented by the following general formula (1), the base polymer contains at least one unit with t being one or more: 
       
         
           
           
               
               
           
         
         wherein R 1  represents a hydrogen atom or a methyl group; and R 2  represents an alkyl group or an alkoxy group having 1 to 6 carbon atoms, wherein t represents an integer of 0 to 2; and s represents an integer of 0 to 4, 
         and one or more monomer unit represented by the following general formula (3); 
       
       
         
           
           
               
               
           
         
         wherein R 4  represents any of a hydroxyl group, an alkyl group, and an alkoxy group having 1 to 6 carbon atoms, wherein v represents an integer of 0 to 4, wherein a hydroxyl group of the general formula (1) is partly protected by an acetal group represented by the following general formula (4); 
       
       
         
           
           
               
               
           
         
         wherein R 5  represents a hydrogen atom, a linear, a branched, or a cyclic alkyl group having 1 to 10 carbon atoms, Y represents a linear or a branched alkyl group having 1 to 30 carbon atoms, and the polymer is insoluble or hardly soluble in an alkaline solution, while soluble in an alkaline solution when deprotected by an acid catalyst, 
         (B) a sulfonium salt containing a sulfonate anion represented by the following general formula (5); 
       
       
         
           
           
               
               
           
         
         (C) a basic component, and 
         (D) an organic solvent. 
       
     
     
       2. The chemically-amplified positive resist composition according to  claim 1 , wherein a photo acid generator of the component (B) is a triaryl sulfonium salt represented by the following general formula (6): 
       
         
           
           
               
               
           
         
         wherein R 6 , R 7 , and R 8  may be the same or different, and represent any of a hydrogen atom, a fluorine atom, a chlorine atom, a nitro group, a linear, a branched, or a cyclic alkyl group and an alkoxy group, substituted or unsubstituted, having 1 to 12 carbon atoms, among R 6  to R 8 , a pair of linkage chain is formed by combinations of two of them, and when the linkage chain is formed, it may be a single bond or an ether bond. 
       
     
     
       3. The chemically-amplified positive resist composition according to  claim 2 , wherein the sulfonium salt represented by the above general formula (6) is a triaryl sulfonium salt represented by the following general formula (7): 
       
         
           
           
               
               
           
         
       
     
     
       4. The chemically-amplified positive resist composition according to  claim 1 , wherein the composition is for an electron beam lithography. 
     
     
       5. The chemically-amplified positive resist composition according to  claim 2 , wherein the composition is for an electron beam lithography. 
     
     
       6. The chemically-amplified positive resist composition according to  claim 3 , wherein the composition is for an electron beam lithography. 
     
     
       7. A resist patterning process comprising at least steps of:
 applying the chemically-amplified positive resist composition according to  claim 1 ; 
 conducting exposure; and 
 developing by using a developer to form a resist pattern on a processing substrate. 
 
     
     
       8. A resist patterning process comprising at least steps of:
 applying the chemically-amplified positive resist composition according to  claim 2 ; 
 conducting exposure; and 
 developing by using a developer to form a resist pattern on a processing substrate. 
 
     
     
       9. A resist patterning process comprising at least steps of:
 applying the chemically-amplified positive resist composition according to  claim 3 ; 
 conducting exposure; and 
 developing by using a developer to form a resist pattern on a processing substrate. 
 
     
     
       10. A resist patterning process comprising at least steps of:
 applying the chemically-amplified positive resist composition according to  claim 4 ; 
 conducting exposure; and 
 developing by using a developer to form a resist pattern on a processing substrate. 
 
     
     
       11. A resist patterning process comprising at least steps of:
 applying the chemically-amplified positive resist composition according to  claim 5 ; 
 conducting exposure; and 
 developing by using a developer to form a resist pattern on a processing substrate. 
 
     
     
       12. A resist patterning process comprising at least steps of:
 applying the chemically-amplified positive resist composition according to  claim 6 ; 
 conducting exposure; and 
 developing by using a developer to form a resist pattern on a processing substrate. 
 
     
     
       13. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 1  on a mask blanks, and then removing an excess solvent component remained in a coat film by heating to obtain a resist film; a step of pattern-exposing by a high energy radiation; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       14. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 2  on a mask blanks, and then removing an excess solvent component remained in a coat film by heating to obtain a resist film; a step of pattern-exposing by a high energy radiation; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       15. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 3  on a mask blanks, and then removing an excess solvent component remained in a coat film by heating to obtain a resist film; a step of pattern-exposing by a high energy radiation; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       16. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 4  on a mask blanks, and then removing an excess solvent component remained in a coat film by heating to obtain a resist film; a step of pattern-exposing by a high energy radiation; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       17. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 5  on a mask blanks, and then removing an excess solvent component remained in a coat film by heating to obtain a resist film; a step of pattern-exposing by a high energy radiation; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       18. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 6  on a mask blanks, and then removing an excess solvent component remained in a coat film by heating to obtain a resist film; a step of pattern-exposing by a high energy radiation; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       19. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 1  on a mask blanks having a formed film of a chrome compound; a step, after a heat-treatment, of pattern-exposure by a high energy radiation via a photo mask or pattern-exposure by a high energy beam; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       20. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 2  on a mask blanks having a formed film of a chrome compound; a step, after a heat-treatment, of pattern-exposure by a high energy radiation via a photo mask or pattern-exposure by a high energy beam; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       21. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 3  on a mask blanks having a formed film of a chrome compound; a step, after a heat-treatment, of pattern-exposure by a high energy radiation via a photo mask or pattern-exposure by a high energy beam; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       22. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 4  on a mask blanks having a formed film of a chrome compound; a step, after a heat-treatment, of pattern-exposure by a high energy radiation via a photo mask or pattern-exposure by a high energy beam; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       23. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 5  on a mask blanks having a formed film of a chrome compound; a step, after a heat-treatment, of pattern-exposure by a high energy radiation via a photo mask or pattern-exposure by a high energy beam; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required. 
     
     
       24. A resist patterning process comprising, at least, a step of applying the chemically-amplified positive resist composition according to  claim 6  on a mask blanks having a formed film of a chrome compound; a step, after a heat-treatment, of pattern-exposure by a high energy radiation via a photo mask or pattern-exposure by a high energy beam; and a step of developing by using a developer, after a heat-treatment is done after a light-exposure as required.